Systems and methods for carbon capture and sequestration and compositions derived therefrom

ABSTRACT

A method of sequestering a greenhouse gas is described, which comprises: (i) providing a solution carrying a first reagent that is capable of reacting with a greenhouse gas; (ii) contacting the solution with a greenhouse gas under conditions that promote a reaction between the at least first reagent and the greenhouse gas to produce at least a first reactant; (iii) providing a porous matrix having interstitial spaces and comprising at least a second reactant; (iv) allowing a solution carrying the at least first reactant to infiltrate at least a substantial portion of the interstitial spaces of the porous matrix under conditions that promote a reaction between the at least first reactant and the at least second reactant to provide at least a first product; and (v) allowing the at least first product to form and fill at least a portion of the interior spaces of the porous matrix, thereby sequestering a greenhouse gas.

RELATED APPLICATION

This application claims priority to US provisional patent applicationSer. No. 60/988,122 filed Nov. 15, 2007, which is herein incorporated byreference in its entirety.

BACKGROUND

Global warming has received increasing attention owing to greateracceptance of proposed theories, which include the increasing release ofcarbon dioxide, a green house gas. Global releases of carbon dioxide was49 billion tons in 2004, which was an 80% increase over 1970 levels. Theemissions of carbon dioxide in 2005 in the USA alone was 6.0 billionmetric tons. Materials in the construction industry, such as steel andcement, generate carbon dioxide, among other toxic and/or greenhousegases, at very significant levels. In 2002, the EPA estimates thatcement production accounts for 5 wt % of the world production of carbondioxide and ties the steel industry for being the most significantindustrial contributors of carbon dioxide. Carbon dioxide release isattributed to three components: First, limestone decomposition, wherecalcium carbonate is calcined (heated) to CaO. Second, energy (about 5million BTU/metric ton of cement) is needed to heat (drive) theendothermic limestone decomposition. Third, electrical energy needed fordriving process equipment such as the rotary calciner and millingequipment. In sum, for every ton of cement produced, 1.08 tons of carbondioxide are generated.

Also, conventional ceramic making involves high temperature processessuch as calcining and sintering. The raw materials are frequentlyrendered reactive for materials manufacturing by powder processes suchas milling, where ceramic fragments, called clinker in the cementindustry, are ground from a centimeter size to a micron size. Evenprocesses such as these are energy intensive. In 1980, milling processesfor ceramic chemicals accounted for about 0.5% of the nations energyconsumption.

Thus, a need exists for a better systems and/or methods for making aceramic that can also minimize the carbon footprint, or even captureand/or sequester the greenhouse gases generated during production.

Furthermore, the post-combustion capture of CO₂ (PCC) from flue-gasremains a challenge. For example, problems such as backpressures canlimit the output of a power plant. Further, the capture process isfrequently limited by the conditions of the combustion, which aredetermined by the chemistry of the fuel being burned as well as theselected combustion conditions. For example, amine-based capture methodsrequire low temperatures for high CO₂ capture efficiency, whichintroduces energy costs for cooling the flue gas and a CO₂ footprintassociated with the energy.

Thus, a need exists to establish a method that can operate over a widerange of fuel and combustion conditions without any efficiency penaltyto the manufacturing concern using that combustion process, remove allof the CO₂ in the gas stream in an economical fashion, consume CO₂ whenall contributions to CO₂ generation have been considered, processmaterials at a cost that can be recovered by the sale of thecommodities, and supply CO₂ in a soluble form.

SUMMARY OF THE INVENTION

One embodiment provides a method of sequestering a greenhouse gascomprising: (i) providing a solution carrying a first reagent that iscapable of reacting with a greenhouse gas; (ii) contacting the solutionwith a greenhouse gas under conditions that promote a reaction betweenthe at least first reagent and the greenhouse gas to produce at least afirst reactant; (iii) providing a porous matrix having interstitialspaces and comprising at least a second reactant; (iv) allowing asolution carrying the at least first reactant to infiltrate at least asubstantial portion of the interstitial spaces of the porous matrixunder conditions that promote a reaction between the at least firstreactant and the at least second reactant to provide at least a firstproduct; and (v) allowing the at least first product to form and fill atleast a portion of the interior spaces of the porous matrix, therebysequestering a greenhouse gas. Reacting can include, for example,dissolution, ion addition, ion substitution, precipitation,disproportionation, or combinations thereof.

Another embodiment provides a ceramic produced by a carbon capturing,carbon sequestering process, or a combination thereof, which processcomprises allowing at least one component of a porous matrix to undergoa reaction with at least a first reactant carried by a infiltratingmedium to provide at least a first product, during which reaction aremainder of the porous matrix acts as a scaffold for facilitating theformation of the first product from the reaction mixture, therebyproducing a ceramic.

In another embodiment, a method of making a ceramic is provided, themethod comprising: (i) providing a porous matrix having interstitialspaces and comprising at least a first reactant; (ii) contacting theporous matrix with an infiltrating medium that carries at least a secondreactant, which comprises a greenhouse gas; (iii) allowing theinfiltrating medium to infiltrate at least a portion of the interiorspaces of the porous matrix under conditions that promote a reactionbetween the at least first reactant and the at least second reactant toprovide at least a first product; and (iv) allowing the at least firstproduct to form and fill at least a portion of the interstitial spacesof the porous matrix, thereby producing a ceramic, wherein the methodconsumes and does not release significant amounts of greenhouse gas.

One embodiment provides a cement comprising substantially no hydraulicbond. A hydraulic bond can be generally referred to as a water-mediatedbond, such as a bond involving at least a water molecule or a portionthereof. For example, it can be a hydrogen bond.

Another embodiment discloses a ceramic comprising ceramic bond, whereinthe ceramic comprises an interconnecting network microstructure. Aceramic bond can be generally referred to as a chemical bonding eitherbetween a metal and a non-metal or a non-metal and a non-metal witheither covalent, ionic, or a mixed ionic-covalent bonding. The chemicalbonding in the preferred embodiment is substantially based on depositionof matter in the adjacent porous structure and not based on Van derWaals or hydrogen bonding. An interconnecting network microstructure canbe generally referred to as a microstructure that has some porosityand/or channels that are connected with each other and are accessiblefrom the surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a FeO phase diagram based on thermodynamic computationgenerated for selection of the reactant species used in the HLPSreaction in one embodiment.

FIG. 2 provides a Ca(OH)₂ phase diagram based on thermodynamiccomputation generated for selection of the reactant species used in theHLPS reaction in one embodiment.

FIG. 3 provides a FeTiO₃ phase diagram based on thermodynamiccomputation generated for selection of the reactant species used in theHLPS reaction in one embodiment.

FIG. 4 provides a Fe₃O₄ phase diagram based on thermodynamic computationgenerated for selection of the reactant species used in the HLPSreaction in one embodiment.

FIG. 5 provides a Fe₃O₄ phase diagram based on thermodynamic computationgenerated for selection of the reactant species used in the HLPSreaction in one embodiment. provides thermodynamic computation resultsfor CaSO₄ and K₂CO₃.

FIG. 6 provides a Ca(OH)₂ and K₂CO₃ phase diagram based on thermodynamiccomputation generated for selection of the reactant species used in theHLPS reaction in one embodiment.

FIG. 7 provides a CaSO₄ and C₂H₂O₄ phase diagram based on thermodynamiccomputation generated for selection of the reactant species used in theHLPS reaction in one embodiment.

FIG. 8 provides a MgO and C₂H₂O₄ phase diagram based on thermodynamiccomputation generated for selection of the reactant species used in theHLPS reaction in one embodiment.

FIG. 9 provides a Ca(OH)₂ and C₂H₂O₄ phase diagram based onthermodynamic computation generated for selection of the reactantspecies used in the HLPS reaction in one embodiment.

FIG. 10 provides a CaSO₄ and K₂H₂O₄ phase diagram based on thermodynamiccomputation generated for selection of the reactant species used in theHLPS reaction in one embodiment.

FIG. 11 provides a Ca(OH)₂ and K₂H₂O₄ phase diagram based onthermodynamic computation generated for selection of the reactantspecies used in the HLPS reaction in one embodiment.

FIG. 12 provides a CaCO₃ and H₂C₂O₄ phase diagram based on thermodynamiccomputation generated for selection of the reactant species used in theHLPS reaction in one embodiment.

FIG. 13 provides a phase diagram for 0.1 mol CaCO₃ and K₂C₂O based onthermodynamic computation generated for selection of the reactantspecies used in the HLPS reaction in one embodiment.

FIG. 14 provides decomposition of a CaCO₃ as a function of pH in oneembodiment.

FIG. 15 provides decomposition of a CaC₂O₄ as a function of pH in oneembodiment.

DETAILED DESCRIPTION OF THE INVENTION

All references cited herein are incorporated by reference in theirentirety.

General Conditions for Hydrothermal Liquid Phase Sintering

In a preferred embodiment of hydrothermal liquid phase sintering (HLPS),a “green” or partially sintered, porous, solid matrix having contiguousinterstitial pores can be transformed into a sintered ceramic by theaction of a liquid phase infiltrating medium. HLPS can be carried outunder relatively mild conditions, frequently not exceeding thetemperature and pressure encountered in a functioning autoclave. HLPScan be performed in a wide range of temperatures and pressures. Forexample, in some embodiments, the HLPS conditions can includetemperature less than about 2000° C., such as less than about 1000° C.,such as less than about 500° C., such as less than about 200° C., suchas less than about 100° C., such as less than about 50° C., such as roomtemperature. The reaction pressure can be less than about 100000 psi,such as less than 70000 psi, such as less than about 50000 psi, such asless than about 10000 psi, such as less than about 5000 psi, such asless than about 1000 psi, such as less than about 500 psi, such as lessthan about 100 psi, such as less than about 50 psi, such as less thanabout 10 psi. In one embodiment, the hydrothermal sintering process canbe carried out at a temperature in the range of about 80° C. to about180° C. and a pressure in the range of about 1 to about 3 atmospheres (1atmosphere is about 15 psi).

In theory, any starting material that is capable of undergoing ahydrothermal reaction with an infiltrating species to produce adifferent substance may be used to produce the hydrothermally sinteredproduct. Hence, a wide variety of starting materials may be selected,depending on the contemplated end use, formed into a porous solid matrixhaving the desired shape and size and, subsequently, subjected to thesteps of the instant method for transformation into the sinteredfinished product.

In one embodiment, the porous solid matrix is derived from a metal oxidepowder. The powder may be amorphous or crystalline, preferablycrystalline. Moreover, the metal oxide powder may have a wide range ofparticulate sizes ranging from a mean particle size of about 0.01 micronto about 100 microns, including for example about 0.02 to about 50microns, such as about 0.04 to about 20 microns, such as about 0.08 toabout 10 microns. In one embodiment, the powder has a mean particle sizeranging from about 0.1 micron to about 5 microns.

The metal in the metal oxide can be chosen from an oxide of a Group Iametal, Group IIb metal, Group IIIb metal, Group IVb metal, Group Vbmetal, transition metal, lanthanide metal, actinide metal or mixturesthereof. Preferably, the chosen metal oxide or the sintered finishedproduct can have potential chemical, ceramic, magnetic, electronic,superconducting, mechanical, structural or even biological applications.The sintered finished product can have industrial or household utility.The finished product need not necessarily comprise the same material asthe reactants. For example, a product substantially free of bariumtitanate, BaTiO₃, may be produced by reactants that comprise bariumand/or titanium. However, in a different embodiment, the barium and/ortitanium comprising reactant (or reactants) can act mostly as anintermediate reaction species, and thus may not necessarily be includedin the final product.

“Hydrothermal reaction” described herein can include transformationstaking place in aqueous or nonaqueous liquid media. Furthermore, suchtransformations may include the dissolution and re-precipitation of thesame chemical species, the dissolution of one chemical species and itscombination with a second chemical species to form a composite materialin which the initial chemical species remain distinct, or the reactionof one chemical species with a second chemical species to produce a newchemical moiety that is distinct from the starting species. Thehydrothermal sintering process thus can fill the interstitial spaces orvoids in a porous solid matrix with a moiety by precipitation (orre-precipitation), ion addition, ion substitution, or a combinationthereof. The moiety can comprise the same chemical species as that inthe solid matrix, a composite resulting from the co-re-precipitation oftwo distinct chemical species, a new product resulting from a reactionbetween two chemical species, a re-precipitated material derived from aninfiltrant species contained in the medium, or a combination thereof.

In one embodiment, a HLPS process can be carried out under conditions inwhich at least a portion of the mass of the green porous solid matrixreacts with preselected infiltrant species present in the fluid mediumto produce a new product.

HLPS Reaction

The hydrothermal reaction process can occur via adissolution-re-precipitation reaction mechanism. Alternatively, thereaction can occur via an ion-substitution reaction. In the former,small portions of the compacted porous solid matrix can dissolvefurnishing dissolved species which can react with the ions in theinfiltrant solution; the ions in the infiltrant solution can be metalions. In one embodiment, the amount of the infiltrant added can beenough to produce the complete reaction in a single step. Alternatively,multiple steps can be involved. For example, multiple infiltration canbe involved. In one embodiment, strontium titanate can be formed from atitania matrix, thereafter by another infiltration it can form strontiumapatite. Alternatively, via multiple infiltrations, a carbonate can beformed, which can then form a protective oxalate layer. In anotherembodiment, the compact can be partially infiltrated and dried, and theinfiltration step can be repeated until the final product is produced.

The shape of the product can be retained from that of the solid matrix.In one embodiment, when the molar volume of the product is greater thanthat of the oxide powder (i.e., a positive molar volume change—i.e.,transformation to a larger molar volume), the nucleated product fillsthe voids of the compact and increases its density. The molar volumechange need not be positive; it can also be negative (i.e.,transformation to a smaller molar volume) or no change depending on theion species and reaction mechanism. For example, a portion of the matrixcan dissolve away during the reaction, increasing porosity whilecreating new chemical bonding and a negative molar volume change.Similarly, if the new material form has the same volume as that from theloss of the matrix, then there is substantially no molar volume change.

HLPS reaction can occur via, for example, ion addition and/or ionsubstitution. Addition reactions are where ions (anions or cations) inthe infiltrating medium can be added to the matrix host withoutsubstituting another ion in the matrix. Examples of an ion addition caninclude transformation from oxide to hydroxide, or from oxide tocarbonate. Examples of an ion substitution can include transformationfrom hydroxide to carbonate, or hydroxide to oxalate. Additionally, thereaction can occur via disproportionation, wherein the insolubleinorganic host/matrix material can be split into two insoluble inorganicproducts. Disproportionation can be performed, for example, for oxides,fluorides, hydroxides, sulfates, mixed metal oxides, silicates,hydroxyapatites.

Heterogeneous nucleation can also take place during the reaction. Asdescribed previously, the change in density can depend on the type ofthe matrix material and/or that of the product formed. Once thehydrothermal reaction is complete, the open pores can be further removedby, for example, aging.

After the reactions as described above are completed, the densifiedmonolithic matrix may be rinsed or bathed in a solution to wash awayexcess infiltrating solution. The rinsing solution can be pH 5 ammoniumacetate. In one embodiment, the densified matrix may be subsequentlydried in an oven at a temperature of about 90° C. to 250° C. Theresidual porosity that may be present in the sintered ceramic can befurther removed by heating to a higher temperature, such as about 600°C. or less.

The ceramic product sintered by the HLPS process can have a variety ofapplications. For example, it can be used a structural, chemical (e.g.,catalyst, filtration), electronic components, semiconductor material,electrical material, or combinations thereof.

Preparation of the Porous Solid Matrix

The solid matrix can comprise a material that does not dissolve in asolution readily. In one embodiment, the porous solid matrix is derivedfrom powder. The powder can be of any kind. For example, it can be ametal oxide powder. Examples of suitable metal oxide powders caninclude, the oxides of berylium (e.g., BeO), magnesium (e.g., MgO),calcium (e.g., CaO, CaO₂), strontium (e.g., SrO), barium (e.g., BaO),scandium (e.g., Sc₂O₃), titanium (e.g., TiO, TiO₂, Ti₂O₃), aluminum(e.g., Al₂O₃), vanadium (e.g., VO, V₂O₃, VO₂, V₂O₅), chromium (e.g.,CrO, Cr₂O₃, CrO₃, CrO₂), manganese (e.g., MnO, Mn₂O₃, MnO₂, Mn₂O₇), iron(e.g., FeO, Fe₂O₃), cobalt (e.g., CoO, CO₂O₃, CO₃O₄), nickel (e.g., NiO,Ni₂O₃), copper (e.g., CuO, Cu₂O), zinc (e.g., ZnO), galluim (e.g.,Ga₂O₃, Ga₂O), germanium (e.g., GeO, GeO₂), tin (e.g., SnO, SnO₂),antimony (e.g., Sb₂O₃, Sb₂O₅), indium (e.g., In₂O₃), cadium (e.g., CdO),silver (e.g., Ag₂O), bismuth (e.g., Bi₂O₃, Bi₂O₅, Bi₂O₄, Bi₂O₃, BiO),gold (e.g., Au₂O₃, Au₂O), zinc (e.g., ZnO), lead (e.g., PbO, PbO₂,Pb₃O₄, Pb₂O₃, Pb₂O), rhodium (e.g., RhO₂, Rh₂O₃), yttrium (e.g., Y₂O₃),ruthenium (e.g., RuO₂, RuO₄), technetium (e.g., Tc₂O, Tc₂O₃, molybdenum(e.g., MoO₂, Mo₂O₅, Mo₂O₃, MoO₃), neodymium (e.g., Nd₂O₃), zirconium(e.g., ZrO₂), lanthanum (e.g., La₂O₃), hafnium (e.g., HfO₂), tantalum(e.g., TaO₂, Ta₂O₅), tungsten (e.g., WO₂, W₂O₅), rhenium (e.g., ReO₂,Re₂O₃), osmium (e.g., OsO, OsO₂, iridium (e.g., IrO₂, IR₂O₃), platinum(e.g., PtO, PtO₂, PtO₃, Pt₂O₃, Pt₃O₄), mercury (e.g., HgO, Hg₂O),thallium (e.g., TlO₂, Tl₂O₃, palladium (e.g., PdO, PdO₂) the lathanideseries oxides, the actinide series and the like. Moreover, dependingupon the particular application involved, mixtures of metal oxides mayalso be used in making the preform.

The matrix can also comprise a hydroxide, such as a metal hydroxide. Forexample, it can comprise magnesium hydroxide (e.g., Mg(OH)₂), calciumhydroxide (e.g., Ca(OH)₂), strontium hydroxide (e.g., Sr(OH)₂), andbarium hydroxide (e.g., Ba(OH)₂), chromium hydroxide (e.g., Cr(OH)₂),titanium hydroxide (e.g., Ti(OH)₂), zirconium hydroxide (e.g., Zr(OH)₄),manganese hydroxide (e.g., Mn(OH)₂), iron hydroxide (e.g., Fe(OH)₂),copper hydroxide (e.g., Cu(OH)₂), zinc hydroxide (e.g., Zn(OH)₂),aluminum hydroxide (e.g., Al(OH)₃), or a combination thereof.

The matrix can also comprise a fluoride, such as a metal fluoride. Forexample, it can comprise magnesium fluoride (e.g., MgF₂), calciumfluoride (e.g., CaF₂), strontium fluoride (e.g., SrF₂), and bariumfluoride (e.g., BaF₂), chromium fluoride (e.g., CrF₂), titanium fluoride(e.g., TiF₃), zirconium fluoride (e.g., ZrF₄), manganese fluoride (e.g.,MnF₂), iron fluoride (e.g., FeF₂), copper fluoride (e.g., CuF₂), nickelfluoride (e.g., NiF₂), zinc fluoride (e.g., ZnF₂), aluminum fluoride(e.g., AlF₃), or combinations thereof.

The matrix can also comprise a mixed metal oxide, such as a metaltitanate. For example, it can comprise magnesium titanate (e.g.,MgTiO₃), calcium titanate (e.g., CaTiO₃), strontium titanate (e.g.,SrTiO₃), barium titanate (e.g., BaTiO₃), or a combinations thereof.

The matrix can also comprise a sulfate, such as a metal sulfate. Forexample, it can comprise magnesium sulfate (e.g., MgSO₄), calciumsulfate (e.g., CaSO₄), strontium sulfate (e.g., SrSO₄), and bariumsulfate (e.g., BaSO₄), chromium sulfate (e.g., Cr₂(SO₄)₃), titaniumsulfate (e.g., TiSO₄, Ti₂(SO4)₃), zirconium sulfate (e.g., ZrSO₄),manganese sulfate (e.g., MnSO₄), iron sulfate (e.g., FeSO₄), coppersulfate (e.g., CuSO₄), nickel sulfate (e.g., NiSO₄), zinc sulfate (e.g.,ZnSO₄), aluminum sulfate (e.g., Al₂(SO₄)₃), or combinations thereof.

The matrix can also comprise a silicate, such as a metal silicate. Forexample, it can comprise lithium metasilicate, lithium orthosilicate,sodium metasilicate, beryllium silicate, calcium silicate, strontiumorthosilicate, barium metasilicate, zirconium silicate, manganesemetasilicate, iron silicate, cobalt orthsilicate, zinc orthosilicate,cadmium metasilicate, andalusite, silimanite, hyanite, kaolinite, orcombinations thereof.

The matrix can also comprise a hydroxyapatite, such as a metalhydroxyapatite. For example, it can comprise calcium carbonate, calciumnitrate tetrahydrate, calcium hydroxide, or combinations thereof.

The matrix can further comprise an inert fill material, in addition toany of the materials mentioned above and others. An inert fill materialcan be any material that is incorporated into the solid matrix to fillthe pores and do not significantly react with the infiltrant to forchemical bonding. For example, the inert material can be wood, plastic,glass, metal, ceramic, ash, or combinations thereof.

The powder can be characterized by a mean particle size, which can rangefrom about 0.005 μm to 500 μm, such as from about 0.01 μm to about 100μm, particle size distribution and specific surface area. A fine meanparticle size and a narrow particle size distribution can be desirablefor enhanced dissolution.

The powder can be formed into a green body of any desired shape and sizevia any conventional technique, including extrusion, injection molding,die pressing, isostatic pressing, and slip casting. Ceramic thin filmscan also be formed. Any lubricants, binders of similar materials used inshaping the compact can be used and should have no deleterious effect onthe resulting materials. Such materials are preferably of the type whichevaporate or burn out on heating at relatively low temperature,preferably below 500° C., leaving no significant residue.

The matrix can comprise, for example, a mineral, an industrial waste, oran industrial chemical material. A mineral can be, for example, amineral silicate, or a gypsum. An industrial waste can be, for example,fly ash, slag, or battery waste. An industrial chemical can be anychemical synthesized or prepared by a factory or an industry in general.

The compact can be formed into the predetermined shape and dimensions ofthe product material. The compact can be in any form. The volume of openporosity of the compact (0-80%) can depend on the ratio of molar volumeof the reaction product to the molar volume of the powder. The productmaterial can be for example a monolithic body, such as a monolithicdense body. In one embodiment, the reaction product formed within thepores of the compact can have a greater molar volume than the powder.The reaction product can have a greater molar volume than the oxidepowder to fill the voids of the compact during the reaction. Forexample, if the molar volume of the reaction product is twice as greatas that of the oxide powder, the compact should have an open porosity ofabout 50% by volume.

The pores in the starting powder compact can be small, for example,between about 0.01 micrometers (μm) and about 100 μm, such as betweenabout 0.1 μm and about 1 μm, and uniformly distributed throughout thecompact, thereby enabling the infiltrant solution to penetrate fully thepowder compact. The pore volume content, both close and open porosity,and the pore size can be determined by standard methods. For example, amercury intrusion pore sizer can be used to evaluate these threeparameters.

The preform obtained above can then be subjected to the steps asdiscussed below.

Preparation of the Infiltrating Medium

As described previously, hydrothermal sintering can make use of aqueousor nonaqueous media. The choice of liquid solvent can depend on theinfiltrant species that may be a part of the infiltrating medium. Theinfiltrant species can have a substantial solubility in the liquidsolvent under the conditions of the hydrothermal sintering process. Forexample, if the infiltrant species are ionic, then a liquid solvent canbe water. Certain nonionic infiltrants may also possess sufficientsolubility in aqueous media.

In addition, water-soluble organic solvents, such as alcohols (e.g.,methanol, ethanol, propanol, isopropanol and the like), polyols (e.g.,ethandiol, 1,2-propanediol, 1,3-propanediol and the like), certain lowmolecular weight ethers (e.g., furan, tetrahydrofuran), amines (e.g.,methylamine, ethylamine, pyridine and the like), low molecular weightketones (e.g., acetone), sulfoxides (e.g., dimethylsulfoxide),acetonitrile and the like, may also be present in the aqueous mixture.In certain instances, surfactants (e.g., polysiloxanes, polyethyleneglycols, and alkyldimethylamine oxides and the like) may be added to theaqueous mixture.

The infiltrating medium preferably contains water-soluble metal salts(i.e., metal in ion forms). The cation of such salts, for example, maycome from the following metals: berylium, magnesium, calcium, strontium,barium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt,nickel, copper zinc, aluminum, gallium, germanium, tin, antimony, indum,cadium, silver, lead, rhodium, ruthenium, technetium, molybdenum,neodymium, zironium, ytterbium, lanthanum hafnium, tantalum, tungsten,rhenium, osmium, iridium, platinum, gold, mercury, thallium, palladium,cations of the lanthanid series metals, cations of the actinide seriesmetals, and or a mixture thereof. In general, the anion of the saltsdissolved in the infiltrating solution may come, for example, from thefollowing groups: hydroxides, nitrates, chlorides, acetates, formates,propionates, phenylacetates, benzoates, hydroxybenzoates,aminobenzoates, methoxybenzoates, nitrobenzoates, sulfates, fluorides,bromides, iodides, carbonates, oxalate, phosphate, citrate, andsilicates, or mixtures thereof. The molar ratio of the metal ionscontained in the infiltrant to the metal ion of the oxide powder can beselected to achieve a desired stoichiometric reaction product. Excessmetal ions in solution may be needed to help achieve completion of thereaction.

Depending on the infiltrating medium and the matrix material, theresultant sintered product can be, for example, a titanate, if amaterial comprising titanium is involved. For example, titanates havinga ilmenite structure can be obtained from TiO₂ and salts of Fe²⁺, Mg²⁺,Mn²⁺, Co²⁺, Ni²⁺, or a combination thereof, in water. Titanates havingthe perovskite structure can be prepared from aqueous salt solutions ofCa²⁺, Sr²⁺, barium ions, or a combination thereof. Moreover, compoundshaving a spinel structure can be obtained including, Mg₂TiO₄, Zn₂TiO₄,and Co₂TiO₄. Furthermore, different phases of barium titanate, such asthat having the formula Ba_(x)Ti_(y)O_(x+2y), in which x and y areintegers, can be obtained by the method of the present invention.

Alternatively, the resultant sintered product can be a carbonate,sulfate, oxalate, or a combination thereof; materials that can be usedcan include a material that may decompose before it is able to sinter ifa conventional sintering method is used; for example a carbonate willdecompose into its oxide when heated before it is able to sinter in aconventional sintering method. The carbonate, sulfate, oxalate, can be,for example, metal carbonate, meta sulfate, meta oxalate, respectively,comprising a cation of an element found on the periodic table.

Characterization of the Sintered Material

Porosity of Sintered Material

HLPS can produce a sintered product with a very homogeneous and veryfine microstructure. The porosity of the sintered material can be, forexample, less than about 15 percent, such as less than about 10 percent,such as than about 5 percent, or even practically fully dense. The totalporosity of the compact can be determined in a standard technique, forexample, with a mercury pore sizer. Density can be estimated using aconventional technique such as Archimede's mercury pore sizer

Size and Shape of Sintered Material

One characteristic of the sintered material undergoing the HLPS processis that it can have the same shape, or even size, as the starting greencompact. In one embodiment wherein the product undergoes substantiallyno molar volume change, no shrinkage of the compact can result, which isin contrast to many ceramic manufacturing processes, and thus little orno machining of the sintered material is needed.

Composition of Sintered Material

As illustrated in the Examples, a broad range of chemical compositionscan be used to make the sintered material. Furthermore, the number ofdifferent metal oxides and salts involved in the formation of thesintered material need not be restricted in any particular way. Inaddition, the stoichiometry of the final product can be dictated by themolar ratios of reactants present in the green compact and infiltratingmedium. The composition of the sintered material can be evaluated usingQuantitative X Ray Diffraction (QXRD) and Inductively Coupled Plasma(ICP).

Microstructure and Related Mechanical Properties

The sintered product of the HLPS process can have a microstructure thatsubstantially resembles a net-like interconnecting network. Themonoliths obtained from the HLPS process can also exhibit compositestructures such as a core-shell structure. In addition, the product canhave superior mechanical properties, such as high tensile strength,compressive strength, and desirable tensile modulus. This strengtheningcan arise from the chemical bonding formed during the process betweenthe physically bonded particles by ion substitution, ion addition,Ostwald ripening (i.e., recrystallization that can form new network), orcombinations thereof. In one embodiment, Ostwald ripening can involveaging a carbonate material in an alkaline medium. Furthermore, in thecase where there is a positive molar volume change, densification can beachieved, as described previously.

Cement-Making by HLPS

Conventionally, cements are made in two steps: (i) they are synthesizedwith high temperature processes and (ii) then are consolidated and boundwith water to make a monolithic structure.

HLPS can integrate the synthesis and consolidate/bonding steps of cementmaking, providing a compact, energy efficient, and environmentallyfriendly process. It can be versatile, using a wide range of rawmaterials, which will allow processes to be used for ingredients thatcan be conveniently accessible (e.g., waste from a factory), therebyminimizing transportation costs.

Instead of making ceramics using high temperature processes, HLPS canprovide an alternative to form a variety of ceramic materials ofinterest in a fluid in mild temperature and/or pressure conditions. Theceramic crystals can be made without using “corrective” millingprocesses as in a convention procedure and have crystal sizes andmorphology with suitable reactivity for making materials. Furthermore,the chemical bond of the product produced by HLPS can be ceramic bonds,or can be substantially free of hydraulic bonds, as generally producedby a convention construction material (i.e., cement) making process.Conventional cements have hydraulic bonding, and as a result, candegrade with respect of its mechanical strength starting at about 200°C.—it can lose almost all of its strength at 1000° C. By substantiallyminimizing formation of hydraulic bonding (that is, bonding involvingwater molecules or portions thereof), the ceramic produced by HLPS canwithstand temperatures at least about 1000° C.

Other benefits of using HLPS to produce cement, or ceramic in general,can include shorter reaction time to form a ceramic product.Hydrothermal reactions can be based on aqueous solution reactions whereceramics can be directly formed from a solution at temperaturestypically less than about 400° C., such as less than 300° C., or atabout room temperature.

The ceramic produced can also be highly dense with substantially nohydraulic bonds and mostly ceramic bonds. For examples, the bonds incements can be created by hydration of the powders slurried in water.Conventional ceramics have most of their bonds created by diffusioninduced by high temperature firing. By contrast, the ceramics of HLPScan be formed by reacting a monolithic compact of powder or solid matrixwith a infiltrating medium to fill the interstitial spaces (i.e., pores)of the particles. The crystals nucleating and growing in theseinterstitial spaces can form chemical bonding to one another and to thepowder matrix to create a ceramic-bonded monolithic body. As a result,unlike a hydraulic cementation process, anhydrous ceramic bonds can beformed, whose stability can be at least about 1000° C., such as about2000° C. Furthermore, unlike a conventional densification process (e.g.,solid state sintering), the reaction temperature can be lower than about90° C., such as room temperature.

As described previously, a product of HLPS process can undergo a changein molar volume (increase or decrease) or substantially no change. Inone embodiment, wherein the molar volume change is positive,densification can also occur. In one embodiment, wherein the solidmatrix can ask as a scaffold for a bonded structure to form,substantially no change in dimensions has occurred. As a result,substantially no defects such as cracks or defects were induced. Whilethe material does not change dimension, the relative porosity of thestructure can be controlled by the choice of the reactive chemistrywhere the percentage molar volume change between the product andreactant can determine the porosity remaining in the structure. Forexample, a 50% porous structure that is reacted to form a product thathas a 100% molar volume change can fully densify. In one embodiment,having a large pore size can be desirable to achieve completeconversion. Note that the initial density can be controlled by bothchoice of the matrix powder and the forming technique for packing thepowders.

There are many reactions where a volume increase or decrease can beengineered to result (see Table 1) to change the porosity while bondingthe ceramic with the crystals that form from the reaction. For example,converting a matrix of CaSO₄ to CaC₂O₄.H₂O can result in a molar volumeincrease (densification) of 44.4 vol %, while converting CaSO₄ to CaCO₃can result in a molar volume decrease (increased porosity) of −19.7 vol%. Control of this process can be further controlled by mixingcomponents of negative and positive volume change to engineer acomposite whose net density (pore fraction) change can be engineered toa either a, zero, positive or negative value. As shown in Table 1, amolar volume increase of as large as 616 vol % and a molar volumedecrease of 50.2 vol % can be possible.

The ability to decrease or increase porosity can have a great utility.For example, large molar volume increases can have utility in lowdensity matrices that can accommodate the large expansion, such asaggregate that can go into road building material or buildingstructures. On the other hand, large volume decreases can be used toimprove transport of reacting solutions that bond aggregate as thereactions proceed by increasing the permeability as the reactionproceeds. In addition, composites can include the addition of inertpowders to reduce a density increase (or decrease), which canproportionately diminish the molar volume increase (or decrease). Ingeneral, whether the reaction results in a volume expansion orcontraction of the matrix, crystals forming from the reaction can serveto bond the matrix, be it a reactant, inert component, or a product thathas already formed from the reaction.

TABLE 1 Density, molecular weight, molar volume, % vol change to itscarbonate, % vol change to its oxalate of starting materials for HLPS.Molar % molar volume % molar volume Starting Volume change to its changeto its Material (cc/mol) carbonate oxalate CaSO₄ 45.99 −19.7 44.4CaSO₄•2H₂O 74.21 −50.23 −10.51 FeO 11.97 148.09 558.94 Fe₂O₃ 15.21 95.33418.8 Fe₃O₄ 14.93 99 428.54 MgO 11.2 146.92 616.28 Mg(OH)₂ 24.61 12.34225.88 MgCO₃ 27.64 0 190.09 Ca(OH)₂ 33.68 9.66 97.2 FeTiO₃ 32.14 −7.58145.48 FeCO₃ 29.71 0 165.6 CaCO₃ (calcite) 36.93 0 79.83

HLPS can provide a method to form ceramic bonds with a variety ofmaterials, including those that cannot be prepared by any conventionprocess. Accordingly, ceramic such as marble, a naturally occurringcalcium carbonate (CaCO₃) can be synthesized from non-carbonated calciumsources.

Because of the versatility of the HLPS process, the process can be usedto capture greenhouse gases, such as carbon dioxide, while forming adense ceramic, as described previously. The process can be furtherintegrated into power-generating facilities that emit greenhouse gases,wherein the gases can be captured and fed directly into the HLPS processas a reactant.

Forming Ceramics by Gas Capture

With the HLPS process, gases can be captured from the atmosphere andused in the reaction to form a variety of ceramics, including marble orcements. The gases can be any type of gas, such as a greenhouse gas,including carbon dioxide, or a gas containing, in general, carbon,sulfur, phosphor, nitrogen, hydrogen, oxygen, or a combination thereof.

Phase diagrams generated by computations based on thermodynamic can beperformed to help with selecting an appropriate reactant for the HLPSprocess. For example, reactions with CaSO₄ and CO₂ may not form CaCO₃,while many other systems were found to react. The following chemicalreactions, with a matrix reacting with CO₂-saturated solutions areaccompanied by the results of its thermodynamic computation, showingsuitability for sequestering carbon dioxide with formation ofcarboxylate compounds. Note that the carbon source and its concentrationis a variable and the other ceramic reactant is held at constantconcentration. For each precursor system, the phases produced werereported for a range of temperatures, including room temperature.FeO+CO₂→FeCO₃  (FIG. 1)Ca(OH)₂+CO₂→CaCO₃+H₂O  (FIG. 2)FeTiO₃+CO₂→FeCO₃+TiO₂  (FIG. 3)Fe₃O₄+CO₂→FeCO₃+Fe₂O₃  (FIG. 4)

Like ilmenite (FeTiO₃), perovskite (CaTiO₃), sphene (CaTiSiO₅) oralkaline earth feldspars (CaAl₂Si₂O₈) can be decomposed into a carbonateand a respective oxide. For reactions such as Fe₂O₄, with an appropriatereducing environment, it may be possible to reduce the Fe³⁺ species suchthat all iron species are divalent and available for carbonation. Oxidesbased on Fe³⁺ are not predicted to form iron carbonates.

For certain materials, CO₂ may not be reactive according to thecomputations. For example, CaSO₄ does not react with soluble CO₂. Inother cases, other means of CO₂ capture may be more advantageous. Forexample, potassium can be converted to potassium hydroxideelectrochemically, thereby capturing carbon dioxide gas to form K₂CO₃and then precipitate CaCO₃ from CaSO₄ as follows:CaSO₄+K₂CO₃→CaCO₃+K₂SO₄  (FIG. 5)

Similar reactions can be performed with carbonate salts of sodium orammonium. In one embodiment, porous marble (i.e., calcium carbonate) canbe prepared, and K₂SO₄ can remain in the structure. Other non-mineralreactants can also be used to capture CO₂, such as Ca(OH)₂.Ca(OH)₂+K₂CO₃→CaCO₃+2KOH  (FIG. 6)

Other suitable alkali carbonates can include Na₂CO₃ and NH₄CO₃. Ingeneral, alkali carbonates can be derived from alkali hydroxides.Reactions involving hydroxides such as the above reaction can return thealkali hydroxide when carbonation occurs. Thus, such a reaction canallow recycling of the alkali hydroxide to capture more CO₂. In oneembodiment, mineral oxides can be used to return the alkali hydroxidewhen a carbonation reaction is used:MO+M′₂CO₃+H₂O→MCO₃+2M′OH,where, M=Na⁺, K⁺, NH₄ ⁺

Iron ore, (Fe₂O₄/Fe₃O₄), which is abundant on earth, can be used.Alternatively, Mg can be used in a reactive sintering process that canbe initiated with limestone as follows:Mg²⁺+K₂CO₃+CaCO₃→MgCO₃/CaCO₃+2K⁺

A porous limestone body thus can be filled with MgCO₃ to make acomposite material.

One important advantage of making a structural material such as acarbonate by capturing a greenhouse gas such as carbon dioxide can bethat carbon dioxide is consumed during the process, and the process doesnot produce significant amounts of greenhouse gases.

Gas Sequestration

In one embodiment, 2 molecules of CO₂ can be sequestered usingmulti-dentate ligands such as oxalate, C₂O₄ ²⁻. This reactant cancomprise two CO₂ molecules bonded together through a carbon-carbon (C—C)bond. Simulations were performed on the following oxalate systems todetermine feasibility of the above, the their respective results areshown in the figures:

H₂C₂O₄CaSO₄+H₂C₂O₄→CaC₂O₄.H₂O+H₂SO₄  (FIG. 7)MgO+H₂C₂O₄+2H₂O→MgC₂O₄.2H₂O+H₂O  (FIG. 8)Ca(OH)₂+H₂C₂O₄→CaC₂O₄.H₂O+H₂O  (FIG. 9)

K₂C₂O₄CaSO₄+K₂C₂O₄+H₂O→CaC₂O₄.H₂O+K₂SO₄  (FIG. 10)Ca(OH)₂+K₂C₂O₄+H₂O→CaC₂O₄.H₂O+2KOH  (FIG. 11)

In some embodiments, the reactions involving carbonate can return KOH asreaction product, which can be can be reused for additional reactions,while sequestering the carbonate. In addition, other oxalates such as(NH₄)₂C₂O₄ and Na₂C₂O₄ can also be used, as can any oxalate precursorthat can provide dissociated oxalate anions. Many oxalates that arestable at room temperature can be used. For example, ferrioxalate,[Fe(C₂O₄)₃]⁻³ can be a soluble anion that can take up to 6 CO₂ atoms periron, which can be desirable for carbon dioxide capture and/orsequestration.

Oxalate salts can also be useful that they can form oxalates and releasecarbon dioxide gas or soluble carbonate as follows:CaCO₃+H₂C₂O₄→CaC₂O₄.H₂O+CO₂  (FIG. 12)CaCO₃+K₂C₂O₄→CaC₂O₄.H₂O+K₂CO₃  (FIG. 13)

The use of carboxylate materials can offer enhanced chemical durabilityover convention cements. For example, conventional marble can begin todecompose at pH of less than about 6 but can endure very high pH levelswithout decomposition (FIG. 14). For example, when oxalates are used forcalcium oxalate monohydrate, pH levels greater than 2 and less than 13can be endured without decomposition (FIG. 15). The lack of a hydraulicbond can also make it less susceptible to salts used to de-ice coldsurfaces.

Applications

One advantage of forming ceramics while capturing and/or sequesteringgreenhouse gases by HLPS processes is the versatility of the processes.For example, the reactions can be initiated at any time, allowing rapidon-site installation of structures. For example, steam-roller typedevices can be used to compact powder and subsequently heat the system,while mixtures of steam and CO₂ initiate the sintering reaction.Alternatively, carbonate solutions can be injected into porous bedsfollowed by roller-based consolidation and heating. Casting forms cancomprise polymer liners that waveguide microwave energy to heat thewater locally to initiate and complete the reaction, where localpressures in the compacted structures can correspond to sub- orsuper-critical reaction conditions. This versatility can allowconstruction projects to have little or no time required for curing ofthe materials. Also, the ability of HLPS processes to add water on-sitecan reduce the weight of construction materials needed for delivery,thereby reducing cost and energy consumption. Furthermore, in HLPS watercan be used as a solvent for the infiltrating medium, rather than areactant, such as in conventional cement. In particular, water in HLPScan be either reused or returned to the ecosystem.

In one embodiment, the gas capture and sequestration processes can becombined in one single process. For example, the a greenhouse gas can becaptured by a reagent capable of reacting with the greenhouse gas.Subsequently, the captured gas (then in aqueous form) can become areactant in the solution, which then act as an infiltrating medium, asdescribed previously, to sequester the gas. Alternatively, a capturingprocess is not used prior to sequestration. For example, theinfiltrating medium can come readily available with at least agreenhouse gas dissolved, and thus only sequestration of the greenhousegas is used in this embodiment. The medium can be a commerciallyavailable product, if desired.

In one embodiment, the ability to construct shrinkage-free processingcan enable formation of a wide range of multicomponent structures,wherein the components other than the bonding phase can reside passivelyin the structure. Such components can be gravel and sand, which canprovide a strong percolative network that can be reinforced by theinterconnected network of bonded carbonate materials that pervadesthrough the pore structure of gravel and sand. Other structures such assteel rebar can also be incorporated, where interfacial reactions canprovide additional reinforcement. Soluble silicate derived from graveland sand can promote this reaction with steel, as well as promote theformation of other silicate compounds that further contribute thebonding phases in the carbonate-based composite structure. The absenceof shrinkage can also promote the embedding of devices in low stressenvironment to facilitate real-time monitoring of the mechanicalstability of the material as well as stress-state.

One additional advantage of the product described herein can includefire resistance, particular for the carbonates. Carbonates, such ascalcium carbonate do not decompose until substantially highertemperatures are reached (about 800 to 1000° C., depending on CaCO₃particle size and partial pressure of CO₂-p_(CO2)).

Inert materials, such as inorganic reflective, colorant, opacifier, orluminescent particles, can also be incorporated in these carboxylateceramics. For example, the decomposition of FeTiO₃, as mentionedearlier, can be used to make composite building materials from titaniaand FeCO₃.

Post-Combustion Carbon Capture

Carboxylates such as metal carbonates and metal oxalates can be used inpost-combustion carbon dioxide capture in a HLPS process. Carbonate ionscan be made from a CO₂ molecule via a fast reaction as follows:CO₂+20H⁻→CO₃ ²⁻+H₂O

Note that water is generated as a co-product. Thus, if large quantitiesof CO₂ are processed, the generation of water can also be beneficial aswater becomes scarce. In one embodiment, 1-2 inorganic cations can beused for each carbonate ion as follows:xM^(z+)+CO₃ ²⁻→M_(x)(CO₃).

For example when the inorganic ion is sodium, the ratio of CO₂ toinorganic product on an atomic percent basis is 1:2, whereas when theinorganic ion is calcium, the ratio of CO₂ to inorganic product on anatomic percent basis is 1:1. Monovalent carbonates can be desirablebecause they can be highly soluble in water.

Metal oxalates also be used. Two molecules of CO₂ are used to make oneoxalate ion as follows:2CO₂+2e ⁻→C₂O₄ ²⁻

This ion can be made either from carbon monoxide or biologically fromCO₂ in a wide range of vegetation. The ability of oxalate to capture 2molecules of CO₂ for each oxalate anion can provide other possibilitiesfor CO₂ capture. For example, minerals, such as limestone, generally candecompose to release CO₂ as follows:CaCO₃→CaO+CO₂

Alternatively, carbonate can be decomposed with the addition of oxalate:CaCO₃+K₂C₂O₄+H₂O→CaC₂O₄.H₂O+K₂CO₃

Thus, CO₃ ²⁻ can be recovered from limestone and generate a K₂CO₃precursor that can be further used in hydrothermal sintering, as opposedto generating CO₂ gas that would require capture. This reaction can alsooccur with the addition of oxalic acid:CaCO₃+H₂C₂O₄→CaC₂O₄.H₂O+CO₂

Calcium hydroxide is generally known to be manufactured by hydratingcalcium oxide in water. Calcium hydroxide can be converted to carbonate,as follows:Ca(OH)₂+CO₂→CaCO₃+H₂O

Thus, this reaction is carbon neutral, as it consumes the CO₂ oncereleased to form CaO. However, if oxalate is used, then the reaction canbe carbon consuming as follows:Ca(OH)₂+H₂C₂O₄→CaC₂O₄.H₂O+H₂OorCa(OH)₂+K₂C₂O₄+H₂O→CaC₂O₄.H₂O+2KOH

In one embodiment, the caustic base generated in the reaction can befurther used as a CO₂ capture solution. Thus, one HLPS process of CO₂capture can begin another HLPS process.

Post-combustion carbon capture solution can be based on solublehydroxide such as caustic soda. Soluble hydroxide can be used as acapture solution via a scrubbing tower.

One advantage of the proposed process is that it can recover all of theheat value of the flue gas, operate at high temperatures, react with CO₂quantitatively and utilize raw materials that can be extracted from anycoastline, which also can be convenient for shipping. The CO₂ footprintcan be very small unless the flue gas is unable to supply the neededheat value for evaporation and carbonation.

NON-LIMITING WORKING EXAMPLES Example 1 Calcium Carbonate from CalciumHydroxide and Potassium Carbonate

Calcium oxide powder, ˜5 g, was reacted with ˜100 ml de-ionized water toform Ca(OH)₂ in Teflon jar at room temperature. The calcium hydroxideand water mixture was cooled down to room temperature. It was thenshaken and poured into colloidal press until the reservoir was filledroughly around 75%. A load of 7000 pounds was applied on the colloidalpress slowly. A Teflon™ jar was filled with 200 ml of de-ionized waterand 30 g of K₂CO₃ was dissolved in it. Wet Ca(OH)₂ pellet was placed ona Teflon tray and placed in the Teflon jar. The cap of the jar wasclosed and kept at room temperature for 4 days. The pellet was thentaken out and rinsed with de-ionized water. The reaction product wassubjected to x-ray diffraction and was found to comprise mainly CaCO₃with a small amount of Ca(OH)₂. The sample maintained its shape and hadsufficient mechanical strength to resist fracture.

Example 2 Calcium Oxalate Monohydrate from Calcium Hydroxide and OxalicAcid

Calcium oxide powder, ˜5 g, was reacted with ˜100 ml de-ionized water toform Ca(OH)₂ in a Teflon™ jar at room temperature. The calcium hydroxideand water mixture was cooled down to room temperature. It was thenshaken and poured into a 1″ diameter colloidal (filter) press until thereservoir was filled roughly around 75%. A load of 7000 pounds wasapplied on the colloidal press slowly. The Teflon jar was filled with200 ml of de-ionized water and 30 g of H₂C₂O₄ were mixed. The wetCa(OH)₂ pellet was placed on a Teflon™ tray and placed in the Teflon™jar. The cap of the jar was closed and kept at room temperature for 4days. The pellet was then taken out and rinsed with de-ionized water.X-ray diffraction revealed the presence of both CaC₂O₄.H₂O and Ca(OH)₂.The sample maintained its shape and size as pressed and did not changedimensions after hydrothermal liquid phase sintering The material ismechanically stable. A more complete reaction and even stronger materialmight result if Ca(OH)₂ was mixed with oxalic acid during pressingrather than using pure water.

The preceding examples and preferred embodiments are meant to illustratethe breadth of the invention and should not be taken to limit theinvention in any way. Other embodiments will surely be apparent to thoseof ordinary skill in view of the detailed descriptions provided in thisdisclosure. Such other embodiments are considered to fall within thescope and spirit of the invention, which is limited solely by thefollowing claims.

What is claimed:
 1. A method of sequestering a greenhouse gascomprising: (i) forming a porous matrix having a predetermined shape andsize; (ii) providing the porous matrix having interstitial spaces andwherein a portion of the porous matrix comprises at least a firstreactant (iii) providing a solution carrying a first reagent that iscapable of reacting with a greenhouse gas; (iv) contacting the solutionwith a greenhouse gas under conditions that promote a reaction betweenthe at least first reagent and the greenhouse gas to produce at least asecond reactant in solution; (v) allowing the at least second reactantin solution to infiltrate at least a substantial portion of theinterstitial spaces of the porous matrix under conditions that promote areaction between the at least second reactant and at least the portionof the porous matrix comprising the at least first reactant to provideat least a first product; and (vi) allowing the at least first productto form and fill at least a portion of the interior spaces of the porousmatrix, thereby sequestering a greenhouse gas.
 2. The method of claim 1,wherein the greenhouse gas comprises at least one of carbon, sulphur,phosphorous, nitrogen, hydrogen, oxygen or a combination thereof.
 3. Themethod of claim 1, wherein the solid matrix after the step (v) has amolar volume substantially the same as that before step (v).
 4. Themethod of claim 1, wherein the solid matrix after the step (v) has amolar volume larger than that before step (v).
 5. The method of claim 1,wherein the solid matrix after the step (v) has a molar volume smallerthan that before step (v).
 6. The method of claim 1, wherein the solidmatrix after the step (v) has a density larger than that before step(v).
 7. The method of claim 1, wherein the greenhouse gases is producedby a factory.
 8. The method of claim 1, wherein the second reactantcomprises at least one of a metal, metal oxide, metal hydroxide, metalsulfate, metal fluoride, metal titanate, or combinations thereof.
 9. Themethod of claim 1, wherein the first reactant comprises oxalate,carbonate, sulfate, phosphate, citrate, metal ion, or combinationsthereof.
 10. The method of claim 1, wherein the first product is formedby precipitation.
 11. The method of claim 1, wherein the first productcomprises a carboxylate, a carbonate, an oxalate, or a combinationthereof.
 12. The method of claim 1, wherein the first product has adecomposition temperature at least about 1000° C.
 13. The method ofclaim 1, wherein the first product has an interconnecting networkmicrostructure.
 14. The method of claim 1, wherein the first reagent isin aqueous form.
 15. The method of claim 1, wherein the method isperformed at a temperature of less than about 300° C.
 16. The method ofclaim 1, wherein the method is performed at room temperature.
 17. Amethod of making a ceramic, comprising: (i) forming a porous matrixhaving a predetermined shape and size; (ii) providing a porous matrixhaving interstitial spaces and wherein a portion of the porous matrixcomprises at least a first reactant; (iii) contacting the porous matrixwith an infiltrating medium that carries at least a second reactant,which comprises a greenhouse gas; (iv) allowing the infiltrating mediumto infiltrate at least a portion of the interior spaces of the porousmatrix under conditions that promote a reaction between the portion ofthe porous matrix comprising at least first reactant and the at leastsecond reactant to provide at least a first product; and (v) allowingthe at least first product to form and fill at least a portion of theinterstitial spaces of the porous matrix, thereby producing a ceramic,wherein the method consumes and does not release significant amounts ofgreenhouse gas.
 18. The method of claim 17, wherein the step (ii) to(iv) are repeated at least once.
 19. A method of sequestering agreenhouse gas comprising: (i) forming a porous matrix having apredetermined shape and size; (ii) providing the porous matrix havinginterstitial spaces and wherein a portion of the porous matrix comprisesat least a first reactant; (iii) providing a solution carrying at leastone greenhouse gas as a second reactant; (iv) allowing the solutioncarrying the at least second reactant to infiltrate at least asubstantial portion of the interstitial spaces of the porous matrixunder conditions that promote a reaction between the at least secondreactant and the portion of the porous matrix comprising the at leastfirst reactant to provide at least a first product; and (v) allowing theat least first product to form and fill at least a portion of theinterior spaces of the porous matrix, thereby sequestering a greenhousegas.
 20. The method of claim 19, wherein the greenhouse gas is dissolvedin the solution.